A gas turbine engine may include a turbine section with multiple rows or stages of stator vanes and rotor blades that interact or react with a high temperature gas flow to create mechanical power. In a gas turbine engine, the turbine rotor blades drive the compressor and an electric generator to generate electrical power. The efficiency of the engine can be increased by passing a higher temperature gas flow through the turbine. However, the turbine inlet temperature is limited to the vane and blade (airfoils) material properties and the cooling capabilities of these airfoils.
Film cooling may be used on the vanes and blades to manage component temperatures. Film cooling involves ejecting cooling air across a surface of a high-temperature part. Round cooling holes may have poor performance due to the lack of a diffuser, yet they are manufacturable within tolerances. Symmetric diffuser designs may theoretically provide more effective cooling performance but lack manufacturability. For example, diffuser holes designed to be completely separate openings may overlap after manufacturing.